低碳钢板坯夹渣缺陷分析及控制

Analysis and control of slag inclusion defects of low carbon steel slab

某炼钢厂生产低碳钢中厚板坯时,在较高拉速(1.6~2.1 m/min)下,铸坯表面质量正常;当拉速降低至1.2~1.3 m/min时,连铸坯表面出现暗灰色无规律分布的长条状及块状质量缺陷;电镜能谱分析表明,缺陷处含有结晶器保护渣。通过建立铸坯传热数学模型,分析了不同拉速下结晶器内温度场分布,并据此优化了保护渣物理化学性能.表面夹渣缺陷率由11.2%降低到0.9%,取得了较好的应用效果。

The surface quality of the slab is normal at a high drawing speed of 1.6-2.1 m/min in the production of medium and thick slab of low carbon steel in a steel plant.When the drawing speed is reduced to 1.2-1.3 m/min,the surface of continuous casting billet presents long strip and block quality defects with irregular distribution of dark grey.The analysis of energy spectrum shows that the defect contains mold slag.By establishing the heat transfer model of the billet,the distribution of temperature field in the mold at different drawing speeds was analyzed,and the physical chemistry properties of the mold flux were optimized accordingly.The surface slag defect rate decreased from 11.2%to 0.9%,and the good application effect was obtained.